Wireless Power Transmission Foreign Substance Detection
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Solution Overview
Problem
Existing wireless power transmission systems face inefficiencies due to prolonged power-transmission stopping times and overheating issues caused by foreign substances, as they lack effective methods for accurate foreign substance detection and efficient power resumption protocols.
Innovation Solution
A power transmission device that includes a memory for storing voltage values, a receiving circuit, an inverter, an oscillator, and a foreign substance detector, which temporarily stops power transmission for detection and resumes it using stored frequency values to minimize stopping time and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If power transmission is temporarily stopped for foreign substance detection, then detection accuracy is improved, but power transmission efficiency deteriorates due to prolonged stopping time
Solution Approach 1:
The system performs foreign substance detection before initiating full power transmission. By detecting the presence of foreign substances in advance using a detection coil and comparison circuit, the system prevents unnecessary power transmission stops, thereby maintaining power transmission efficiency while ensuring detection accuracy.
Solution Approach 2:
The system continuously monitors for foreign substances during power transmission through periodic detection cycles. The control unit manages switching between detection and transmission modes to minimize interruption time, allowing power transmission to resume quickly after detection, thus maintaining continuous useful action and high efficiency.
2Object-affected harmful factors
If power transmission is stopped for foreign substance detection, then foreign substance overheating is prevented, but power transmission time increases
Solution Approach 1:
The system performs foreign substance detection before initiating full power transmission. By detecting the presence of foreign substances in advance using a detection coil and comparison circuit, the system prevents unnecessary power transmission stops, thereby maintaining power transmission efficiency while ensuring detection accuracy.
Solution Approach 2:
The system uses a feedback mechanism where the detection coil continuously monitors for foreign substances, and the control unit adjusts power transmission based on detection results. When foreign substances are detected, power transmission is stopped; when not detected, transmission continues or resumes, creating a closed-loop control that minimizes stopping time while preventing overheating.
3Measurement precision
If detection sensitivity is increased to detect all foreign substances, then detection accuracy is improved, but false detection increases affecting power transmission stability
Solution Approach 1:
The system uses different coils with different characteristics for detection and power transmission. The detection coil is optimized for sensitivity to foreign substances, while the power transmission coil is optimized for efficient power transfer. This separation allows the detection system to be highly sensitive without causing false detections that would destabilize the overall power transmission system.
Solution Approach 2:
The system uses a feedback mechanism where the detection coil continuously monitors for foreign substances, and the control unit adjusts power transmission based on detection results. When foreign substances are detected, power transmission is stopped; when not detected, transmission continues or resumes, creating a closed-loop control that minimizes stopping time while preventing overheating.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces power-transmission stopping time, enhances detection accuracy, and maintains high efficiency by using stored frequency values for resuming power transmission, thus preventing foreign substance overheating and improving overall system performance.
Implementation Method 1
a magnetic-field resonance scheme (a resonance magnetic-field coupling scheme)
Implementation Method 2
an electromagnetic induction scheme
Implementation Method 3
a resonance magnetic-field coupling scheme
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a first power transmission period, a power transmission device holds, in a memory, a value indicating a frequency f0 corresponding to an actual voltage value that matches a requested voltage value, then causes first AC power to be transmitted by using the frequency f0, and uses a foreign substance detector to determine whether or not a foreign substance is present. When it is determined that no foreign substance is present, in a second power transmission period, the power transmission device causes the power transmission of the first AC power to be resumed by using the value indicating the frequency f0, the value being held in the memory.